Tic-Tac-Toe with Automatic Turns and Board Snapshots
Company: Databricks
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: medium
Interview Round: Onsite
Implement the state transitions of a two-player Tic-Tac-Toe game. A successful move places the current player's mark, automatically switches players if play can continue, and produces a board snapshot for display. A win or a full-board draw ends the game.
Implement `play_tic_tac_toe(moves: int[][]) -> string[][]`. Each input row is an attempted `[row, column]`. Return one output row per attempt, using seven strings in this exact order:
```text
[accepted, board_row_0, board_row_1, board_row_2, status, next_player, attempted_player]
```
- `accepted` is `"1"` when a mark was placed and `"0"` otherwise.
- Each board row is a length-three string using `X`, `O`, and `.`.
- `status` is `IN_PROGRESS`, `X_WON`, `O_WON`, or `DRAW`.
- `next_player` is `X` or `O` during play, otherwise `-`.
- `attempted_player` is the player whose turn it was before the attempt; after the game ends it is `-` for all further attempts.
This homogeneous string-matrix encoding makes snapshots portable across languages. A caller can print each snapshot after receiving it.
### Constraints & Assumptions
- The board is 3 by 3 and initially empty. `X` starts.
- There are at most 100 attempts, each with integer coordinates from 0 through 2.
- An occupied-cell attempt is rejected without changing the board or player.
- Attempts after a terminal result are rejected without changing the final state.
- Check for a win before declaring a full board a draw.
- Every output row is an independent snapshot; later moves cannot change prior results.
- Starting-player, invalid-move, and serialization rules are explicit practice assumptions. The reported automated-player extension is a separate exercise.
### Examples
```text
moves = [[0,0],[1,1]]
result = [
["1","X..","...","...","IN_PROGRESS","O","X"],
["1","X..",".O.","...","IN_PROGRESS","X","O"]
]
```
```text
moves = [[0,0],[0,0]]
result = [
["1","X..","...","...","IN_PROGRESS","O","X"],
["0","X..","...","...","IN_PROGRESS","O","O"]
]
```
```hint Keep the transition order explicit
Separate checking whether a move is allowed, applying it, detecting a terminal result, and choosing whose turn comes next.
```
Overview: Implement two-player Tic-Tac-Toe with automatic turn changes, board snapshots, rejected moves, winning lines, and full-board draws.
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